Can a lockable Teensy be used as normal?

C

clinker8

Well-known member
Sparkfun isn't seemingly having fun keeping Teensy's in stock. I don't need the lock function. Can I use a lockable Teensy as a "normal" one? Sometimes Sparkfun has lockable one's available and not normal ones. Will the Teensy flasher make me lock a lockable one?

Just want to know if the lockable Teensy's can be used for general purposes. Ok? Or a bad idea? Thanks.
 
Even after you lock it into secure mode, you can still upload programs from Arduino IDE as you normally would. But once secure, only your computer(s) with your key.pem file can create the .EHEX file to upload because it will only run programs created with your key.
 
I understand the whole concept of locking and why it's good for protecting IP. At the moment, I don't need lockable devices, but I'd like to buy a Teensy or two and only lockable ones are available.

My dumb question is more of, can I use a lockable one as normal device? It takes concerted effort to lock it?
So it's unlikely that someone who's not intending to lock it is relatively safe from blunder?
 
@clinker8: <This> page provides the details on using a lockable Teensy. As others have already answered, as long as you don't execute the steps detailed on that page, the lockable Teensy operates exactly the same as a non-lockable Teensy. So, yes, you can use a lockable one as a normal device, and you can't accidentally lock it.

Hope that helps . . .

Good luck & have fun !!

Mark J Culross
KD5RXT
 
kd5rxt-mark said:
@clinker8: <This> page provides the details on using a lockable Teensy. As others have already answered, as long as you don't execute the steps detailed on that page, the lockable Teensy operates exactly the same as a non-lockable Teensy. So, yes, you can use a lockable one as a normal device, and you can't accidentally lock it.

Hope that helps . . .

Good luck & have fun !!

Mark J Culross
KD5RXT
Click to expand...
Thanks. Been using up my spare Teensies, so needed a couple in reserve.
 
clinker8 said:
It takes concerted effort to lock it?
So it's unlikely that someone who's not intending to lock it is relatively safe from blunder?
Click to expand...

Standard Teensy is safer.

But as long as you don't mess with altering the "fuse memory", Lockable Teensy works the same as Standard Teensy. Writing to the fuses is not a thing normally done by regular programs.

If you do try writing to the fuses, on Standard Teensy you simply can not alter any critically important fuses. On Lockable Teensy you can. Oh how I wish NXP would have designed the chip to separate protection of boot hardware configuration from the security stuff. But the reality of the hardware we have is to allow locking secure mode also means fuses that affect hardware startup are writeable. If you do write to those fuses, which doesn't happen with any of the normal code... you really do have to mess around with special code, but if you do your Lockable Teensy can become forever bricked.

You can also go wrong with Lockable Teensy by using it properly, but then accidentally deleting your key.pem file. Or your computer stops working or gets stolen. Or you get a new machine but don't migrate all your data. You do regularly back up your computer, and retain older backups, right? {insert Anakin & Padme meme here} Seriously though, Lockable Teensy security is quite good. If you lose your key, you'll forever be unable to create new .EHEX files compatible with all the Lockable Teensy boards you've locked into secure mode with that key. Of all the possible risks, the lost key scenario is probably the most likely. Not an issue if you never even use the secure utility feature to create a key. But if you do, please make backup copies of your key.pem file and keep them in a safe place.

Standard Teensy is always able to run ordinary unencrypted .HEX files, even if you've created a key and written it into fuse memory. This is why Standard Teensy isn't considered secure, even if you use encryption. But it also means even if you tried to use encryption and later lost your key, you can still use it with unencrypted .HEX files. You just can't configure Standard Teensy into a mode where it won't allow new code.

Standard Teensy is safer from blunders.
 
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Current use is to just have another couple devices in inventory and for helper tasks. At this point don't even know where or how to mess with fuses, so I hope I'm safe.

I'm currently using a Mac for development and have a backup daily, since Time machine makes that easy. My code is in git, which makes fooling around, ie branching, painless. Have a private repo as well as local ones

But yeah, losing an encryption key gives me nightmares. Lost one to "time", that stuff is gone. Fortunately, the lost stuff wasn't all that important, but it's irrecoverable. Lesson learned.
 
clinker8 said:
Current use is to just have another couple devices in inventory and for helper tasks. At this point don't even know where or how to mess with fuses, so I hope I'm safe.

I'm currently using a Mac for development and have a backup daily, since Time machine makes that easy. My code is in git, which makes fooling around, ie branching, painless. Have a private repo as well as local ones

But yeah, losing an encryption key gives me nightmares. Lost one to "time", that stuff is gone. Fortunately, the lost stuff wasn't all that important, but it's irrecoverable. Lesson learned.
Click to expand...
DigiKey have loads of stock of Teensy 4.1 with or without Ethernet, with or without headers and free postage for 2 Teensy 4.1s.
 
Looks like Digikey ran out of standard Teensy 4.1 without pins. But they still have some with pins soldered, and some of the other versions.

I see ProtoSupplies and Adafruit have stock today on standard Teensy 4.1.

protosupplies.com

Teensy 4.1 - ProtoSupplies

Teensy 4.1 runs the worlds fastest microcontroller the i.MX RT1062 ARM Cortex-M7 at 600MHz or higher and is Arduino Compatible!
protosupplies.com protosupplies.com

www.adafruit.com

PJRC Teensy 4.1 Development Board

The Teensy 4.1, like the 4.0, also features an ARM Cortex-M7 processor at 600 MHz, with an NXP iMXRT1062 chip, the fastest microcontroller available today - ten times faster than ...
www.adafruit.com www.adafruit.com
 
I ordered the lockable ones 4.0 & 4.1 from Sparkfun last night. Guess there's still supply issues, which is a pity.

IMHO @PaulStoffregen created an awesome part. Good thing some of the supply issues were offloaded, frees Paul up to do other stuff.
 
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